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Biomedical subjects

S Nixon

Publications and source records attributed to S Nixon.

10 recordsLinked to original sources
PubMed2005

Aerobic exercise interventions for adults living with HIV/AIDS.

BACKGROUND: The profile of HIV infection is constantly changing. Although once viewed as an illness progressing to death, among those with access to antiretroviral therapy, HIV can now present as a disease with an uncertain natural history, perhaps a chronic manageable disease for some. This increased chronicity of HIV infection has been mirrored by increased prevalence of disablement in the HIV-infected population (Rusch 2004). Thus, the needs of these individuals have increasingly included the management of impairments (problems with body function or structure as a significant deviation or loss, such as pain or weakness), activity limitations (difficulties an individual may have in executing activities, such as inability to walk) and participation restrictions (problems an individual may experiences in involvement in life situations, such as inability to work) (WHO 2001). Exercise is a key strategy employed by people living with HIV/AIDS and by rehabilitation professionals to address these issues. Exercise has been shown to improve strength, cardiovascular function and psychological status in seronegative populations (Bouchard 1993), but what are the effects of exercise for adults living with HIV? If the risks and benefits of exercise for people living with HIV are better understood, appropriate exercise may be undertaken by those living with HIV/AIDS and appropriate exercise prescription may be practiced by healthcare providers. If effective and safe, exercise may enhance the effectiveness of HIV management, thus improving the overall outcome for adults living with HIV. OBJECTIVES: To examine the safety and effectiveness of aerobic exercise interventions on immunological/virological, cardiopulmonary and psychological parameters in adults living with HIV/AIDS. SEARCH STRATEGY: To identify the appropriate studies, we conducted a search using MEDLINE, EMBASE, SCIENCE CITATION INDEX, AIDSLINE, CINAHL, HEALTHSTAR, PSYCHLIT, SOCIOFILE, SCI, SSCI, ERIC and DAI. We also reviewed both published and unpublished abstracts and proceedings from major international and national HIV/AIDS conferences such as the Intersciences Conference on Antimicrobial Agents and Chemotherapy (ICAAC), the Conference on Retroviruses and Opportunistic Infections (CROI), the Infectious Diseases Society of America Conference (IDSA) and the International AIDS Conference (IAC). Reference lists from pertinent articles and books were reviewed and personal contacts with authors were used, as well as Collaborative Review Group databases. Targeted journals were handsearched for relevant articles. There were no language restrictions. Searches for the original review covered the period from 1980 to July 1999. The first update of this review included an additional search of the literature, followed by identification of included studies that met the inclusion criteria from August 1999 to January 2001. For the second update, we conducted a search to identify additional studies published from February 2001 to August 2003. SELECTION CRITERIA: Studies were included if they were randomized controlled trials (RCTs) comparing aerobic exercise interventions with no aerobic exercise interventions or another exercise or treatment modality, performed at least three times per week for at least four weeks among adults (18 years of age or older) living with HIV/AIDS. DATA COLLECTION AND ANALYSIS: Data on study design, participants, interventions, outcomes and methodological quality were abstracted from studies that met the inclusion criteria onto specifically designed data collection forms by at least two reviewers. Meta-analysis was conducted using RevMan 4.2 computer software on outcomes whenever possible. MAIN RESULTS: A total of 10 studies (six from the original search, two from the first updated search and two from this second updated search) met the inclusion criteria for this review. Main results indicated that performing constant or interval aerobic exercise, or a combination of constant aerobic exercise and progressive resistive exercise for at least 20 minutes, at least three times per week for four weeks appears to be safe and may lead to significant reductions in depressive symptoms and potentially clinically important improvements in cardiopulmonary fitness. These findings are limited to those participants who continued to exercise and for whom there was adequate follow-up data. AUTHORS' CONCLUSIONS: Aerobic exercise appears to be safe and may be beneficial for adults living with HIV/AIDS. These findings are limited by the small sample sizes and large withdrawal rates of the included studies. Future research would benefit from an increased attention to participant follow-up and intention-to-treat analysis. Further research is required to determine the optimal parameters of aerobic exercise and stage of disease in which aerobic exercise may be most beneficial for adults living with HIV.

Adult↗
PubMed2004

Progressive resistive exercise interventions for adults living with HIV/AIDS.

BACKGROUND: Due to medical advancements, many people living with HIV infection in developed countries are living longer (Palella 1998). HIV infection can now present as a chronic illness with an uncertain natural disease history. The changing course of HIV infection has lead to a potential increase in the prevalence and impact of disability in people living with HIV infection. Exercise is one key management strategy used by health care professionals to address impairments (problems with body function or structure as a significant deviation or loss such as pain or weakness), activity limitations (difficulties an individual may have in executing activities such as inability to walk) and participation restrictions (problems an individual may experience in life situations such as inability to work) in this population (World Health Organization 2001). Exercise may also be used to address unwanted changes in weight and body composition in people living with HIV infection. Aerobic exercise has been associated with improvements in strength, cardiovascular function, and psychological status in general populations (Bouchard 1993). Results of a systematic review suggested that aerobic exercise interventions appeared to be safe and may lead to improvements in cardiopulmonary fitness for adults living with HIV/AIDS (Nixon 2002). But what are the effects of progressive resistive exercise (PRE) for adults living with HIV infection?A better understanding of the effectiveness and safety of progressive resistive exercise will enable people living with HIV and their health care workers to practice effective and appropriate exercise prescription, thus contributing to improved overall outcomes for adults living with HIV infection. OBJECTIVES: To examine the safety and effectiveness of progressive resistive exercise interventions on weight, body composition, strength, immunological/virological, cardiopulmonary and psychological parameters in adults living with HIV infection. SEARCH STRATEGY: To identify studies to be included in this review, we searched the following databases: MEDLINE, EMBASE, CINAHL, COCHRANE, SCIENCE CITATION INDEX, PSYCHINFO, SOCIOLOGICAL ABSTRACTS, SSCI, ERIC, DAI and HEALTHSTAR. We also reviewed both published and unpublished abstracts and proceedings from major international and national HIV/AIDS conferences such as the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), the Conference on Retroviruses and Opportunistic Infections (CROI), the Infectious Diseases Society of America Conference (IDSA), and the International AIDS Conference (IAC). Reference lists from pertinent articles and books were reviewed, as well as Collaborative Review Group databases. Targeted journals were also hand searched for relevant articles. No language restriction was applied. The search strategy covered literature from 1980-August 2003. SELECTION CRITERIA: We included studies that were randomized controlled trials (RCTs) comparing progressive resistive exercise interventions with no progressive resistive exercise or another exercise or treatment modality, performed at least three times per week, and lasting at least four weeks among adults (18 years of age or older) living with HIV/AIDS. DATA COLLECTION AND ANALYSIS: Data collection forms were used by reviewers to abstract data pertaining to study design, participants, interventions, outcomes and methodological quality from the studies that met inclusion criteria. Whenever possible, meta-analyses were conducted on outcomes using RevMan 4.2.2 computer software. MAIN RESULTS: Seven studies met the inclusion criteria for this systematic review. Meta-analysis was limited due to the following differences among the studies: types of exercise interventions, inclusion of co-intervention groups, level of exercise supervision, baseline body composition and testosterone levels of participants, types of outcomes assessed, and methodological quality of the individual studies.Main results indicated that performing progressive resistive exercise or a combination of progressive resistive exercise and aerobic exercise at least three times a week for at least four weeks appears to be safe and may lead to statistically and possibly clinically important increases in body weight and composition. Results also indicate exercise interventions may lead to clinically important improvements in cardiopulmonary fitness. Individual studies included in this review suggest that progressive resistive exercise interventions with or without aerobic exercise also contribute to improvements in strength and psychological status for adults living with HIV/AIDS. Individual studies indicate that progressive resistive exercise or a combination of progressive resistive and aerobic exercise appears to be safe for adults living with HIV/AIDS who are medically stable as a result of no change seen in immunological/virological status. These results are limited to those who continued to exercise and for whom there were adequate follow-up data. REVIEWERS' CONCLUSIONS: Progressive resistive exercise or a combination of progressive resistive exercise and aerobic exercise appear to be safe and may be beneficial for adults living with HIV/AIDS. These findings are limited by the small number of studies that could be included in meta-analyses, small sample sizes and variable participant withdrawal rates among included studies. Future research would benefit from including participants at various stages of HIV infection, a greater proportion of female participants, and participants in a variety of age groups to increase the generalizability of results. Furthermore, future research would benefit from studies with larger sample sizes that conduct an "intention-to-treat" analysis (analysis of participants based on the groups to which they were originally allocated) to better understand outcomes of participants that withdraw from exercise interventions.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Use of antiretroviral therapy among HIV positive individuals living in British Columbia.

The objective of this study was to examine the level of antiretroviral use and characterize individuals accessing antiretroviral therapy in British Columbia. The study was conducted by the British Columbia Persons with AIDS Society and the British Columbia Centre for Excellence in HIV/AIDS. Self-administered questionnaires were mailed out to HIV-positive members from May to September of 2002. Comparisons of sociodemographic characteristics and disease status were made using Pearson's Chi2 and the Kruskal-Wallis test for continuous variables. A total of 764 (51%) HIV-positive participants returned the questionnaire. Of these, 80% reported ever using antiretroviral therapy and 64.5% indicated current use. Reasons for never taking antiretroviral therapy were high CD4 or doctor's advice (74/126; 59%), feeling healthy (50/126; 40%) and being afraid of side-effects (35/126; 28%). Those reporting current antiretroviral use were more likely to be older (p<0.001), white (p=0.01), male (p<0.001), gay or bisexual (p<0.001), graduated from high school (p=0.001), non-injecting drug user (IDU) (p<0.001) and earning a household income greater than CAN$10,000/year (p=0.003). IDU status and length of time since diagnosis remained significantly associated with antiretroviral use in multivariate models. The differences in current antiretroviral use by sociodemographic characteristics such as IDU suggest that the need remains to target marginalized populations in order to maximize the health benefits from antiretroviral therapy.

Adult↗
PubMed2001

Aerobic exercise interventions for people with HIV/AIDS.

BACKGROUND: The profile of HIV infection is constantly changing. Although once viewed as an illness progressing to death, HIV infection now presents as a chronic infection characterized by unpredictable cycles of wellness and illness. Thus, the needs of this population have increasingly included management of impairments, disabilities and handicaps. Exercise is a key management strategy employed by rehabilitation professionals to address these issues. Exercise has been shown to improve strength, cardiovascular function, and psychological status in seronegative populations (see Eds., Bouchard, C., Shephard, R.J., & Stephens, T. (1993). Physical Activity, Fitness, and Health. Champaign, IL: Human Kinetics Publishers.) But what are the effects of exercise for people living with HIV infection? If the risks and benefits of exercise for people living with HIV infection are better understood, appropriate exercise prescription may be practiced by health care providers. Improved exercise prescription may enhance the effectiveness of HIV management, thus improving overall outcomes for people living with HIV infection. OBJECTIVES: To examine the effect of aerobic exercise interventions on cardiopulmonary, immunologic and psychological parameters in adults living with HIV infection. SEARCH STRATEGY: Studies were identified using MEDLINE, EMBASE, SCIENCE CITATION INDEX, AIDSLINE CINAHL, HEALTHSTAR, PSYCHLIT, SOCIOFILE, SCI, SSCI, ERIC, DIA and abstracts from international AIDS meetings, ICAAC, and other major meetings. Reference lists from pertinent articles and books and personal contact with authors were also used, as were Collaborative Review Group databases and results of hand searching of targeted journals. All languages were included. Searches covered the period from 1980 to July 1999. SELECTION CRITERIA: For inclusion, studies had to be randomized control trials involving HIV+ adults 18 years of age or older and had to include at least one group randomized to receive aerobic exercise performed at least three times/week for at least four weeks. DATA COLLECTION AND ANALYSIS: Data on study design, participants, interventions, and outcomes were extracted from the reports onto specifically designed data collection forms by at least two reviewers. MAIN RESULTS: Six studies satisfied the eligibility criteria. The main results indicated that performing constant or interval aerobic exercise for at least 20 minutes, at least three times per week for four weeks may lead to increased CD4 count, improved cardiopulmonary fitness, and improved psychological status. These findings are limited to those who continued to exercise and for whom there was adequate follow-up data. REVIEWER'S CONCLUSIONS: Aerobic exercise appears to be safe and may be beneficial for adults living with HIV/AIDS. These findings are limited by the small sample sizes and large drop-out rates of the included studies. Further research is required to determine the optimal parameters of aerobic exercise and stage of disease in which aerobic exercise may be most beneficial for adults living with HIV infection.

CD4 Lymphocyte Count↗
PubMed2001

Altered emotional perception in alcoholics: deficits in affective prosody comprehension.

BACKGROUND: Affective prosody is a nonlinguistic aspect of language that conveys emotion and attitude during discourse. It is a dominant function of the right hemisphere. Because skills associated with the right hemisphere have been found to be impaired in alcoholics, this study explored the possibility that affective prosodic functioning may be sensitive to the effects of alcohol due to heavy persistent drinking or prenatal exposure. METHODS: Subjects were aged 25 to 58 years. Twenty-nine men and three women who met DSM-IV criteria for an alcohol use disorder with a median of 39 days of sobriety, 11 men with a probable history of fetal alcohol exposure (FAexp), and 41 age-matched control subjects of both sexes were tested by using the Aprosodia Battery. This instrument assesses affective prosodic comprehension (APC) across a range of verbal articulatory demands. RESULTS: The alcoholic group scored 2 SD below the control mean, and the FAexp group scored -5 SD regardless of whether they had ever been diagnosed with alcohol abuse. Despite their poor performance on APC, alcoholic and FAexp groups performed similarly to the control group on vocabulary, abstract reasoning, and an index of cognitive impairment that used the Shipley Institute of Living Scale. Multiple regression analyses that used nine alcohol use variables to model APC resulted in four significant contributors to the effect. These regressors were related to early exposure to ethanol and chronicity of alcohol abuse. CONCLUSIONS: Alcoholics and FAexp subjects were significantly less accurate at APC compared with controls. These alcohol-exposed subjects appear to be deficient in the ability to understand emotional valence in the speech of others, which results in errors of judgment that may impair social interactions.

Adult↗
PubMed1999

Direct interaction of EEA1 with Rab5b.

The early endosomal autoantigen EEA1 is essential for early endosomal membrane fusion. It binds to endosomes via a C-terminal domain (EEA1-CT). To identify proteins interacting with EEA1-CT, we screened a human brain library in the yeast two-hybrid system. Fourteen clones reacted strongly with EEA1-CT. Sequencing of these clones revealed that they all contained the ORF of the small GTPase, Rab5b. Further two-hybrid analysis suggested that Rab5b also interacts with the N-terminus of EEA1 (EEA1-NT). The interaction of both EEA1-CT and EEA1-NT with Rab5b was confirmed biochemically, and was found to be GTP dependent. Confocal immunofluorescence microscopy indicated that EEA1 colocalizes with Rab5b on early endosomes. Although EEA1-CT and EEA1-NT interacted strongly with wild-type Rab5b in the two-hybrid system, we detected no interaction with wild-type Rab5a, even though GTPase-deficient mutants of both Rab5a and Rab5b interacted equally well with EEA1. This difference could not be explained by differences in intrinsic GTPase activities, as these were found to be very similar. Instead, we speculate that yeast may contain a GTPase-activating protein (GAP) activity that stimulates Rab5a but not Rab5b. In contrast, pig brain cytosol was found to contain a GAP activity that stimulates the GTPase activity of Rab5b in preference to that of Rab5a. These data provide evidence that EEA1 interacts with both Rab5a and Rab5b, and that the GTPase activities of the two proteins are differentially regulated in vivo.

Animals↗
PubMed1986

Social cognition in parents: inferential and affective reactions to children of three age levels.

The present research proposes and tests an attributional model of parent cognition. Derived from correspondent inference theory, the model emphasizes that parents assess children's behavior primarily by determining whether that behavior reflects children's intentions and dispositions or, instead, constraints on children's control of behavior from situational pressures or developmental limitations in knowledge and ability. In 2 studies, support was obtained for 4 predictions. First, findings show that parents' assessments of children's behavior are closely tied to the developmental level of the child. As children developed, parents thought children's behavior was increasingly caused by personality dispositions and was increasingly intentional, under the child's control, and, for misconduct, understood to be wrong. Second, parents' affective reactions to misconduct were related to their assessments of its cause and, third, became increasingly negative as children developed. Positive affect, in contrast, was unrelated to attributions for children's positive behavior. Fourth, parents' assessments of children's behavior were affected by the behavior's desirability. Parents thought children's altruism was more intentional, dispositional, and under the child's control than children's misconduct. Implications for how parents assess and react to children's behavior are discussed.

Adolescent↗
PubMedDate not supplied

A randomized phase II trial of indole-3-carbinol in the treatment of vulvar intraepithelial neoplasia.

The aim of this study was to determine the potential therapeutic benefits of indole-3-carbinol (I3C) in the management of vulvar intraepithelial neoplasia (VIN). Women with histologically confirmed high-grade VIN were randomized to receive 200 and 400 mg/day of I3C. Symptomatology by visual analog scale and vulvoscopic appearance were assessed at recruitment, 6 weeks, 3 months, and 6 months. Tissue biopsy to determine histologic response was obtained at completion of the study period. Urine samples were obtained at each visit to determine 2-hydroxyestrone to 16-alpha-hydroxyestrone ratios. Data from 12 women were suitable for analysis. There was a significant improvement in symptomatology with the introduction of I3C (itch, P= 0.018; pain, P= 0.028). Lesion size and severity were also significantly reduced (size, P= 0.005; appearance, P= 0.046). In addition, there was a significant increase in 2-hydroxyestrone to 16-alpha-hydroxyestrone ratio following commencement of I3C, P= 0.05. However, tissue biopsy from the worst-affected vulval areas revealed no improvement in grade of VIN during the 6-month period, P= 0.317. There were no significant differences in results between those women taking 200 mg/day of I3C and those on 400 mg/day. This study has shown significant clinical improvement in symptomatology and vulvoscopic appearance of VIN with I3C therapy. Further clinical and scientific investigations are required to support these preliminary findings.

Adult↗